Schizophrenia is a severe long-term mental health condition.1
The condition may develop slowly. The first signs can be hard to identify as they often develop during the teenage years.2
The symptoms of schizophrenia are usually classified into:2
positive symptoms – any change in behaviour or thoughts, such as hallucinations or delusions
negative symptoms – a withdrawal or lack of function that you would not usually expect to see in a healthy person; for example, people with schizophrenia often appear emotionless and flat.
The exact causes of schizophrenia are unknown. Research suggests a combination of physical, genetic, psychological and environmental factors can make a person more likely to develop the condition.
Some people may be prone to schizophrenia, and a stressful or emotional life event might trigger a psychotic episode. However, it’s not known why some people develop symptoms while others don’t.3
Bipolar disorder is characterised by extreme mood swings. These can range from extreme highs (mania) to extreme lows (depression).
Episodes of mania and depression often last for several weeks or months.4
Bipolar disorder is a condition of extremes. A person with the condition may be unaware they’re in the manic phase.
After the episode is over, they may be shocked at their behaviour. However, at the time, they may believe other people are being negative or unhelpful4
The exact cause of bipolar disorder is unknown. Experts believe there are a number of factors that work together to make a person more likely to develop the condition.
These are thought to be a complex mix of physical, environmental and social factors.5
Bipolar disorder is widely believed to be the result of chemical imbalances in the brain.
The chemicals responsible for controlling the brain’s functions are called neurotransmitters and include noradrenaline, serotonin and dopamine.5,6
Major Depressive Disorder (MDD)
The symptoms of depression can be complex and vary widely between people. But as a general rule, if you’re depressed, you feel sad, hopeless and lose interest in things you used to enjoy.
The symptoms persist for weeks or months and are bad enough to interfere with your work, social life and family life.7
There’s no single cause of depression. It can occur for a variety of reasons and it has many different triggers.
For some people, an upsetting or stressful life event, such as bereavement, divorce, illness, redundancy and job or money worries, can be the cause.
Different causes can often combine to trigger depression. For example, you may feel low after being ill and then experience a traumatic event, such as a bereavement, which brings on depression.8